CATALOGUE OF TUNICATA. 



83 



The. reproductive organs are placed in a short post-abdomen behind 

 the intestinal loop (fig. 2). 



Locality. Port Jackson ; one colony. 



Polyclinum prunum, n. sp., PI. Pel. IV., figs. 14 16. 



External appearance. The colony consists of a globular mass placed 

 on a short peduncle. The surface is smooth and even, and the Ascidio- 

 zooids are inconspicuous. The colour is a dull yellowish grey, the 

 peduncle being slightly darker and encrusted with sand (fig. 14). Length 

 4'6 cm., breadth 5'2 cm., thickness 3 - 5 cm. Length of peduncle 1 cm., 

 thickness of peduncle 1'2 cm. 



The Ascidiozooids are retracted into the test ; each is about 7 mm. in 

 length, and is divided into thorax, abdomen, and post-abdomen (fig. 15). 

 Tailed larvae are present in the thorax. 



The test is much crowded with test cells, many of which are fusiform. 

 There are no bladder cells and no vessels, but a few yellow pigment 

 cells are present. The outer layer forms a firm membrane over the 

 much softer mass inside. 



The mantle is opaque. Longitudinal muscle fibres run over the 

 thorax, and stronger ones along the post-abdomen. The branchial 

 aperture has 6 lobes ; the atrial aperture is rather irregularly lobed. 



The branchial sac is very opaque, and much corrugated. There are 

 many rows of small stigmata, which are about twice as long as wide. 

 The stigmata are wider than the inter-stigmatic vessels (fig. 16). 



The dorsal lamina is represented by long slender languets, one 

 opposite each transverse vessel (fig. 16). 



The tentacles are very numerous. There are more than 20, closely 

 placed, and of different sizes. 



The dorsal tubercle has a small triangular opening. The neural gland 

 is large. 



The alimentary canal has a short oesophagus, entering a cordate 

 stomach placed with the wider end posterior. The stomach wall is not 

 grooved (fig. 15). The wide intestine runs for some distance posteriorly, 

 and then turns and ends about two-thirds of the way up the dorsal edge 

 of the branchial sac. 



The reproductive organs consist of many spermatic vesicles, placed in 

 the post-abdomen, with a conspicuous vas deferens and a few ova 

 (fig. 15). 



Locality. Port Jackson ; one colony. 



